Ubuntu GUI sometimes uses a lot of cpu thanks to Compiz, which is a problem when I need to run heavy jobs (to be fair, Ubuntu 13.10 is way better than its predecessors in this aspect)!

To turn off the graphic interface, start the terminal mode by typing CTRL+ALT+F1. Then use the command

$sudo service lightdm stop

To restart the graphic interface, use the command

$sudo service lightdm start

setup tabs in Vim?

Type

$set expandtab

to tranform tabs into spaces. Then

$set tabstop=2

to setup tabsize to be equal to 2 spaces. Then

$retab

and

$set shiftwidth=2

to set spaces in indentation.

fix boot?

GRUB bootloader requires some tweaks after installing ubuntu or windows. To fix that, I use the open software boot-repair

updating EOL release?

Ubuntu upgrades usually cause incompatibility problems w/ commercial programs I use. Then, I upgraded my server w/ 13.10 to 14.04 release only six months after 13.10 became EOL. I followed the steps below

Edit the Ubuntu source list

$sudo -i gedit /etc/apt/sources.list

in order to replace the release name to trusty in the repository addresses. Then

$sudo apt-get update

$sudo apt-get upgrade

$sudo apt-get install ubuntu-desktop

$sudo apt-get dist-upgrade

followed by reboot, which failed. However, I was able to fix GRUB w/ boot-repair.